1. Field of the Invention
The present invention is directed to a high-density plastic composite to be used for inertia bodies of various mechanical and electric appliances, which is not only characterized in high-strength and rustproofing, but also provides aesthetic and colored products. This invention is also referred to the process for manufacturing the composite.
2. Prior Art
Because of its cost and the excellent molding characteristics, plastic materials have become widely used in various machine parts and electric appliances.
A property of plastic materials is that the density is lower than most of prior materials, especially metals. Although it is an advantage for making light weight products, but on the contrary, the property becomes a great disadvantage when the use requires heavy parts, such as flywheel, etc.
Two procedures are employed for manufacturing high-density (apparent) products by plastic materials. One procedure is using composite materials highly filled with metal powders, and other is to assemble metal parts with plastic parts.
But, some high-density plastic composite of prior art often decomposes by the action of metal ion eluted from metal powder, which cause chain scission of polymer, and dramatically decrease the mechanical properties of the composite. Another defect of the prior art is that some kinds of metal filler rusts to lose aesthetic appearances of the product, or since it gives only dark colored products and coloring is necessarily limited, the application of the materials for exterior parts is limited.
In the later procedure, manufacturing of metal parts, insert molding or work for assembling are required, which lose the greatest advantage of the plastic molding, namely, producing the parts by only one step.